I just called a Verizon rep who said I have to wait til 10/14 to upgrade or pay full price. He was not only unsympathetic, he blamed Apple for enforcing the subsidy rules - and proceeded to push me to buy an Android device.
I'm going to check with Best Buy to see what they can do. Shame that Verizon doesn't seem to care about helping owners willing to do a 2-year upgrade. I've had the iPhone 4 with Verizon from day one and am ready to upgrade. But if I wait til 10/14 (the earliest I'm technically allowed to upgrade online), it could be weeks before it ships - if demand is high.